The development of a closed-loop artificial pancreas (AP) represents a major technological effort that aims to improve glucose control, prevent complications, and decrease disease burden for patients with diabetes. An AP consists of three components: 1) a subcutaneous glucose monitor, 2) a subcutaneous insulin pump, and 3) an automated control algorithm (Fig. 1) (1,2). Until recently, clinical trials investigating AP function were limited to controlled, in-hospital settings (1,3). However, several recent studies showed that an AP can maintain (4) or even improve (5) glycemic control outside of the hospital.

FIG. 1.

Schematic overview of a closed-loop AP. A closed-loop AP consists of a glucose sensor, an insulin pump, and a control algorithm. The algorithm controls insulin infusion rate based on recent glucose values, recent insulin infusion, and individual-specific information on insulin sensitivity. The latter is often initially derived from body weight, and total and basal insulin doses. In addition, the algorithm needs information on physical activity and meal announcement. Incorporating individual diurnal insulin sensitivity patterns possibly may improve algorithm performance.

Several types of control algorithms have been developed. On the one hand, proportional-integrative derivative algorithms use a classical …